The 20 Incher is a great stonefly imitation that won't take you 30 minutes to tie like some patterns out there, and it will catch just as many fish. Overall, it is just a great pattern that can be easily tailored to imitate just about any stonefly nymph out there.
Material List:
Hook: MFC 7231 #6
Tail: Brown Goose Biots
Body: 3-5 Peacock Herl Strands
Rib: Tan UTC 140 Thread (2 Strands Twisted)
Wing Case: Turkey Tail Feathers
Legs: Brown Partridge Hackle
Thorax: Natural Hare's Mask Dubbing
Bead: 5/32" Brass or Tungsten
